US5746886A - Method for the recovery of energy and chemicals from cellulose spent liquor containing potassium using a gasifier - Google Patents
Method for the recovery of energy and chemicals from cellulose spent liquor containing potassium using a gasifier Download PDFInfo
- Publication number
- US5746886A US5746886A US08/491,893 US49189395A US5746886A US 5746886 A US5746886 A US 5746886A US 49189395 A US49189395 A US 49189395A US 5746886 A US5746886 A US 5746886A
- Authority
- US
- United States
- Prior art keywords
- potassium
- cooking liquor
- reactor
- alkali metal
- sodium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/12—Combustion of pulp liquors
- D21C11/125—Decomposition of the pulp liquors in reducing atmosphere or in the absence of oxidants, i.e. gasification or pyrolysis
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/04—Regeneration of pulp liquors or effluent waste waters of alkali lye
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/06—Treatment of pulp gases; Recovery of the heat content of the gases; Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds
- D21C11/063—Treatment of gas streams comprising solid matter, e.g. the ashes resulting from the combustion of black liquor
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
Definitions
- the present invention relates to a method for recovery of energy and chemicals from cellulose spent liquors having a high content of potassium, wherein the cellulose spent liquor is subjected to partial oxidation at 400°-1200° C. in a reactor, with evolution of a combustible gas and the potassium compounds formed under these conditions being separated and withdrawn from the combustible gas and dissolved in a liquid in order to prepare cooking liquor.
- the closed effluent-free pulp mill has for a long time beckoned as being the final goal to satisfy all environmental demands.
- the aim should therefore be to seek to limit the effluents to as great an extent as possible and convert them into a manageable form in order eventually to be able to return the residues to their source as a constituent part of the natural cycle.
- TCF bleaching based on final bleaching with peroxides in combination with ozone, will completely eliminate the effluents of organic chlorine compounds, thereby eliminating of one of the most serious environmental problems.
- Another option for achieving a high degree of mill closure, while retaining the need for evaporation, is based on the principle of returning all liquid countercurrent through the bleaching plant and in this way transferring both chemicals and released organic substance to the recovery.
- this method leads to other types of problem, including the build-up and enrichment of heavy metals in the bleaching plant to levels which become critical for the process.
- kidneys could, for example, consist of efficient filters or osmotic membranes.
- a prerequisite for efficiently separating the impurities is that it is mainly present in suspended form.
- a common feature of all the abovementioned processes is the fact that potassium, which is supplied in considerable quantity together with the wood used as raw material, is enriched in the recovery system as the degree of closure increases. Potassium compounds are readily soluble in the alkaline liquids which are used in the process, and normally potassium follow sodium and sulphur, and are bled out from the modern mill principally through washing losses. Consequently, efforts to decrease the washing losses will cause the potassium content to increase in circulating liquors.
- the present invention relates to a method for producing pulp which is cooked in an alkaline manner using an integrated recovery system based on partial combustion of black liquors, in which method liquors having a high content of potassium do not interfere with the process.
- U.S. Pat. No. 3,020,195 describes a system for producing potassium carbonate in association with conventional pulp production using potassium-based cooking chemicals.
- the system is based on wholly or partially using a conventional recovery boiler for producing cooking chemicals and potassium carbonate. It is indicated, inter alia, that a significant advantage of the system is the fact that the recovery boiler can be operated at a lower temperature owing to the lower fusion point of the potassium salts.
- U.S. Pat. No. 4,735,683 likewise describes a method for producing potassium salts in association with the production of sulphite pulp using potassium-based cooking chemicals.
- chemicals and energy are recovered using traditional technology in the form of a smelter furnace or fluid bed boiler working wholly or partially under oxidizing conditions, with consequent problems in the form of corrosion and the accretion of potassium compounds which fuse at low temperature.
- CA 1,109,611 describes a potassium-based kraft pulp process in which chlorides are eliminated by evaporation and crystallizing from green liquor or white liquor.
- the recovery of energy and chemicals is said to be effected by combustion, with the formation of a smelt containing potassium carbonate.
- the patent specification does not describe the conditions under which the combustion takes place, nor is there any information on the production of a combustible gas in conjunction with the recovery, something which is an important feature of the present invention and enables efficient energy recovery, for example in an associated gas turbine plant.
- the present invention thus relates to a cooking and chemical recovery system for preparing chemical pulp, which system is in the main potassium-based.
- the concentration of potassium in the recovery cycle varies from mill to mill, mainly depending on the potassium content of the wood used as raw material and on the extent of mill closure.
- the wood which is used as raw material contains on average 0.5-0.8 kg of potassium/ADTP, and even with limited closure of the mill the content of potassium in the liquors builds up to levels which are critical for operation of the recovery boiler.
- the content of sodium in the wood used as raw material is usually significantly lower, or on average 0.05-0.1 kg of sodium/ADTP.
- the cooking liquid can mainly consist of potassium hydroxide and/or potassium carbonate, where appropriate in the presence of one or more delignification catalysts, such as, for example, anthraquinone.
- Potassium has a higher vapour pressure than sodium and, for this reason, the fine particles and aerosols which develop during gasification and combustion of black liquors have a higher K/Na ratio than that pertaining in smelt and black liquor.
- One method of bleeding out potassium from present-day recovery systems is based on this fact and is carried out in practice by purging electrostatic filter ash which is also enriched with regard to chloride.
- the properties of the salt smelt also alter per se. Inter alia, the fusion point falls and the tendency of the dust carried over into the recovery boiler to form accretions increases.
- a high content of potassium in the black liquor can eventually limit the steam temperature in the recovery boiler to 450° C. or lower, due to minimize corrosion of the superheater tubes.
- energy and chemicals are thus recovered from cellulose spent liquors having a high content of potassium by means of partial oxidation in a reactor while an oxygen-containing gas is being supplied.
- the temperature in the reactor is adjusted to between 400° C. and 1200° C., more preferably between 600° C. and 850° C.
- the combustible gas which is formed in association with the partial oxidation is separated from its content of solid and/or liquid alkali metal compounds and finally oxidized at a high temperature in a combustion chamber connected to a steam/heating boiler or gas turbine.
- the alkali metal compounds separated from the process gas are dissolved in a liquid, which liquid is used for preparing new cooking liquor.
- the high content of potassium in the black liquor affects the ratio between the potassium sulphide and sodium sulphide formed in the reactor in a manner which is significant for the process in the present invention.
- the surprisingly high affinity between sulphur and potassium under the pertaining gasification conditions results in the molar ratio between potassium sulphide and sodium sulphide, calculated as K 2 S/K 2 S+Na 2 S, in the smelt or the separated alkali exceeding 0.4 when the potassium/sodium ratio in the black liquor, calculated as K/K+Na, barely exceeds 0.25. This in turn affects the fusion point. Eutectic mixtures in the system K 2 S, K 2 CO 3 , KCl, Na 2 S and Na 2 CO 3 fuse at temperatures which are even lower than 500° C.
- the mechanism of the catalytic effect exerted by potassium in association with combustion/gasification is the subject of extensive studies of both theoretical and experimental nature.
- the view which currently prevails is that the potassium catalyst oscillates between two oxidation states during the reaction, thereby facilitating transport of the oxygen molecule from the gas phase to the reactive carbon surface.
- the catalytic effect of potassium, in combination with the smelt properties of potassium compounds, makes it possible to operate a suspension bed gasifier at a lower temperature, while retaining the degree of carbon conversion, than is possible with corresponding operation using a sodium-based system.
- the key data are shown for gasification of a potassium-based black liquor having a potassium/sodium molar ratio, calculated as K/K+Na, of 0.8.
- K/K+Na potassium/sodium molar ratio
- the potassium carbonate is highly soluble in water, resulting in that the carbonate remains in solution even when present in high concentrations in green liquor/white liquor; this is in contrast to sodium carbonate, which tends to be precipitated from the solution at higher concentrations.
- An alkaline cooking and recovery system having mainly potassium as its base can thus, in this or another expedient manner, be supplemented with a system for eliminating chloride, if this should be found to be necessary.
- the recovery system proposed in the present invention for cellulose spent liquors having a high potassium content can advantageously be integrated with the process described in SE-B-465039, in which sulphur compounds are supplied to the reactor in order to prevent carbonate formation.
- the principle is based on sulphur having a greater affinity for alkali metal than does carbon dioxide under the conditions pertaining in the reaction zone.
- Other possible additives having similar properties, and used with a view to limiting the formation of carbonate in the reactor are certain metal oxides, principally titanium and manganese compounds.
Landscapes
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
______________________________________ Green liquor Sulphide 0.25-0.9 molality Carbonate 1.2-1.8 " Chloride 0.5-1.0 " Sulphate 0.01-0.02 " K + Na 3-7 " K/K + Na 0.5-0.9 molar ratio White liquor Hydroxide 2.2-3 molality Sulphide 0.25-0.9 " Carbonate 0.1-0.4 " Chloride 0.5-1.0 " Sulphate 0.01-0.02 " K + Na 3-7 " K/K + Na 0.6-0.9 molar ratio ______________________________________
______________________________________ Example ______________________________________ Black liquor Alkali metal base Sodium base K/Na + K = 0.9 Flow kg TS/h 1000 1178 Kg TS/kg ADTP 1.5 1.77 Calorific value, 14.4 12.3 calorimetrical (MJ/kg TS) Air Temperature °C. 500 500 Air factor 0.415 0.375 Reactor Temperature °C. 950 800 Pressure, bar 25 25 Carbon conversion, % 99.0 99.0 Gas from the gasifier CO % by vol. 15.3 12.4 H.sub.2 " 17.6 19.9 CH.sub.4 " 0.05 1.12 CO.sub.2 " 12.0 14.4 N.sub.2 " balance balance H.sub.2 S " 0.7 0.5 COS " 0.03 0.015 Gas flow Nm.sup.3 /h 2613 2551 Calorific value MJ/Nm.sup.3 (dry gas) 3.8 4.1 Smelt from the gasifier Na.sub.2 CO.sub.3 % by weight 71.3 6.6 Na.sub.2 S " 20.0 0.6 NaCl " 0.7 0 NaOH (C) " 8.0 0.7 K.sub.2 CO.sub.3 0 63.3 K.sub.2 S 0 26.0 KCl 0 0.6 KOH 0 2.2 Smelt quantity kg/h 420 642.4 Calorific value in combustion gas kw/ADTP (HHV) 3940 4110 ______________________________________
Claims (13)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9300199 | 1993-01-25 | ||
SE9300199A SE9300199L (en) | 1993-01-25 | 1993-01-25 | Method for recycling cellulosic liquids |
PCT/SE1994/000028 WO1994017240A1 (en) | 1993-01-25 | 1994-01-18 | Method for the recovery of cellulose spent liquors |
Publications (1)
Publication Number | Publication Date |
---|---|
US5746886A true US5746886A (en) | 1998-05-05 |
Family
ID=20388636
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/491,893 Expired - Lifetime US5746886A (en) | 1993-01-25 | 1994-01-18 | Method for the recovery of energy and chemicals from cellulose spent liquor containing potassium using a gasifier |
Country Status (10)
Country | Link |
---|---|
US (1) | US5746886A (en) |
EP (1) | EP0680531B1 (en) |
AT (1) | ATE158035T1 (en) |
AU (1) | AU5981494A (en) |
CA (1) | CA2153983A1 (en) |
DE (1) | DE69405537T2 (en) |
ES (1) | ES2107186T3 (en) |
FI (1) | FI111389B (en) |
SE (1) | SE9300199L (en) |
WO (1) | WO1994017240A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6425976B1 (en) * | 1997-10-15 | 2002-07-30 | Aga Ab | Method for black liquor gasification in recovery boilers |
US6514379B1 (en) * | 1999-11-03 | 2003-02-04 | Metso Paper, Inc. | Procedure for arranging water circulations in integrated paper mill |
US20050076568A1 (en) * | 2003-10-09 | 2005-04-14 | Stigsson Lars Lennart | Partial oxidation of cellulose spent pulping liquor |
US8690977B2 (en) | 2009-06-25 | 2014-04-08 | Sustainable Waste Power Systems, Inc. | Garbage in power out (GIPO) thermal conversion process |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE9300199L (en) * | 1993-01-25 | 1994-07-26 | Kvaerner Pulping Tech | Method for recycling cellulosic liquids |
US5715763A (en) * | 1995-09-11 | 1998-02-10 | The Mead Corporation | Combustion system for a black liquor recovery boiler |
FR2761088B1 (en) * | 1997-03-20 | 1999-05-28 | Balcke Duerr Swenson Sa | PROCESS FOR THE RECOVERY OF SODIUM SULFATE FROM SOLID PARTICLES ARISING FROM THE INCINERATION OF BLACK LIQUORS OF STATIONERY AND CORRESPONDING INSTALLATION |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3020195A (en) * | 1960-02-29 | 1962-02-06 | Glatfelter Co P H | Production of potassium compounds |
CA1109611A (en) * | 1978-05-12 | 1981-09-29 | Erco Envirotech Ltd. | Potassium-based pulp mill process |
US4692209A (en) * | 1983-04-21 | 1987-09-08 | Skf Steel Engineering Ab | Recovery of chemicals from pulp waste liquor |
US4735683A (en) * | 1985-05-28 | 1988-04-05 | Potash Corporation Of Saskatchewan | Process for preparation of potassium salts from pulp of lignocellulosic materials |
US4738835A (en) * | 1985-05-22 | 1988-04-19 | A. Ahlstrom Corporation | Method of recovering alkali chemicals from flue gases containing alkali metal vapor |
US4808264A (en) * | 1985-06-03 | 1989-02-28 | Kignell Jean Erik | Process for chemicals and energy recovery from waste liquors |
WO1991008337A1 (en) * | 1989-11-23 | 1991-06-13 | Eka Nobel Ab | A process for the preparation of cooking liquors having high sulphidity for sulphate pulp cooking |
SE464921B (en) * | 1987-06-25 | 1991-07-01 | Skf Plasma Tech | SAVED TO RECOVER CHEMICALS FROM MASS DEVICES |
WO1994017240A1 (en) * | 1993-01-25 | 1994-08-04 | Kvaerner Pulping Technologies Ab | Method for the recovery of cellulose spent liquors |
-
1993
- 1993-01-25 SE SE9300199A patent/SE9300199L/en not_active Application Discontinuation
-
1994
- 1994-01-18 WO PCT/SE1994/000028 patent/WO1994017240A1/en active IP Right Grant
- 1994-01-18 AT AT94905888T patent/ATE158035T1/en not_active IP Right Cessation
- 1994-01-18 DE DE69405537T patent/DE69405537T2/en not_active Expired - Fee Related
- 1994-01-18 US US08/491,893 patent/US5746886A/en not_active Expired - Lifetime
- 1994-01-18 AU AU59814/94A patent/AU5981494A/en not_active Abandoned
- 1994-01-18 EP EP94905888A patent/EP0680531B1/en not_active Expired - Lifetime
- 1994-01-18 ES ES94905888T patent/ES2107186T3/en not_active Expired - Lifetime
- 1994-01-18 CA CA002153983A patent/CA2153983A1/en not_active Abandoned
-
1995
- 1995-07-24 FI FI953539A patent/FI111389B/en not_active IP Right Cessation
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3020195A (en) * | 1960-02-29 | 1962-02-06 | Glatfelter Co P H | Production of potassium compounds |
CA1109611A (en) * | 1978-05-12 | 1981-09-29 | Erco Envirotech Ltd. | Potassium-based pulp mill process |
US4692209A (en) * | 1983-04-21 | 1987-09-08 | Skf Steel Engineering Ab | Recovery of chemicals from pulp waste liquor |
US4738835A (en) * | 1985-05-22 | 1988-04-19 | A. Ahlstrom Corporation | Method of recovering alkali chemicals from flue gases containing alkali metal vapor |
US4735683A (en) * | 1985-05-28 | 1988-04-05 | Potash Corporation Of Saskatchewan | Process for preparation of potassium salts from pulp of lignocellulosic materials |
US4808264A (en) * | 1985-06-03 | 1989-02-28 | Kignell Jean Erik | Process for chemicals and energy recovery from waste liquors |
SE464921B (en) * | 1987-06-25 | 1991-07-01 | Skf Plasma Tech | SAVED TO RECOVER CHEMICALS FROM MASS DEVICES |
WO1991008337A1 (en) * | 1989-11-23 | 1991-06-13 | Eka Nobel Ab | A process for the preparation of cooking liquors having high sulphidity for sulphate pulp cooking |
EP0502052A1 (en) * | 1989-11-23 | 1992-09-09 | Eka Nobel Ab | A process for the preparation of cooking liquors having high sulphidity for sulphate pulp cooking. |
WO1994017240A1 (en) * | 1993-01-25 | 1994-08-04 | Kvaerner Pulping Technologies Ab | Method for the recovery of cellulose spent liquors |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6425976B1 (en) * | 1997-10-15 | 2002-07-30 | Aga Ab | Method for black liquor gasification in recovery boilers |
US6514379B1 (en) * | 1999-11-03 | 2003-02-04 | Metso Paper, Inc. | Procedure for arranging water circulations in integrated paper mill |
US20050076568A1 (en) * | 2003-10-09 | 2005-04-14 | Stigsson Lars Lennart | Partial oxidation of cellulose spent pulping liquor |
US8690977B2 (en) | 2009-06-25 | 2014-04-08 | Sustainable Waste Power Systems, Inc. | Garbage in power out (GIPO) thermal conversion process |
US9850439B2 (en) | 2009-06-25 | 2017-12-26 | Sustainable Waste Power Systems, Inc. | Garbage in power out (GIPO) thermal conversion process |
Also Published As
Publication number | Publication date |
---|---|
DE69405537D1 (en) | 1997-10-16 |
ES2107186T3 (en) | 1997-11-16 |
FI953539A0 (en) | 1995-07-24 |
FI111389B (en) | 2003-07-15 |
DE69405537T2 (en) | 1998-02-12 |
SE9300199D0 (en) | 1993-01-25 |
AU5981494A (en) | 1994-08-15 |
EP0680531B1 (en) | 1997-09-10 |
FI953539A (en) | 1995-07-24 |
CA2153983A1 (en) | 1994-08-04 |
WO1994017240A1 (en) | 1994-08-04 |
ATE158035T1 (en) | 1997-09-15 |
SE9300199L (en) | 1994-07-26 |
EP0680531A1 (en) | 1995-11-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU677827B2 (en) | A method of separating sulphur compounds | |
NZ207797A (en) | Recovery of chemicals from pulp waste liquor | |
US4098639A (en) | Process for reducing the requirement of fresh chemicals without increasing emissions in the pulping of cellulosic material | |
US5746886A (en) | Method for the recovery of energy and chemicals from cellulose spent liquor containing potassium using a gasifier | |
US6027609A (en) | Pulp-mill recovery installation for recovering chemicals and energy from cellulose spent liquor using multiple gasifiers | |
US3909344A (en) | Removal of sodium chloride from pulp mill operations | |
CA2116017C (en) | Production of sodium hydroxide | |
US3331732A (en) | Method of removing hydrogen sulfide from an aqueous solution of alkali sulfide | |
RU2117629C1 (en) | Method of preparing hydrogen peroxide for bleaching of cellulose | |
US5174860A (en) | Low temperature recovery of kraft black liquor | |
FI62363B (en) | FOERFARANDE FOER AOTERVINNING AV SODIUM CHLORIDE FRAON CELLULOSAFABRIKENS PROCESSER | |
US3950217A (en) | Removal of sodium chloride from pulping operations | |
US3986923A (en) | Removal of dissolved salts from sulphide liquors | |
US5597445A (en) | Method for recovering sodium from a spent cooking liquor | |
US4249990A (en) | Process for removal of potassium values from pulp mill liquors | |
CA1064206A (en) | Method of recovering substances in the extraction of spent liquors from the delignification of lignocellulosic material by means of chloride-producing bleaching agents | |
US5814189A (en) | Method for gasifying cellulose spent liquor to produce superheated steam and green liquor of low carbonate concentration | |
US5628872A (en) | Method for bleaching pulp with hydrogen peroxide recovered from cellulosic spent liquor | |
CA2241138A1 (en) | Process for the conversion of calcium sulfide | |
US20040194900A1 (en) | Method for recovery of pulping chemicals in an alkaline sulphite pulping process and for production of steam | |
US3248169A (en) | Method of regenerating sodium sulfite waste liquors | |
EP0745155A1 (en) | Process for separating off chloride from sulphide-containing alkaline liquor | |
JOHANSON | Development of a Volatile Sulfur Recovery Process for Kraft Pulping |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: KVAERNER PULPING TECHNOLOGIES,AB, SWEDEN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BACKLUND, AKE;STIGSSON, LARS;REEL/FRAME:007632/0450;SIGNING DATES FROM 19950627 TO 19950703 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
AS | Assignment |
Owner name: KVAERNER CHEMREC AKTIEBOLAG, SWEDEN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KVAERNER PULPING AB;REEL/FRAME:011627/0516 Effective date: 19990326 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: CHEMREC AKTIEBOLAG, SWEDEN Free format text: CHANGE OF NAME;ASSIGNOR:KVAERNER CHEMREC AKTIEBOLAG;REEL/FRAME:015400/0049 Effective date: 20040414 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FPAY | Fee payment |
Year of fee payment: 12 |